Pyrrole modified biomass derived hierarchical porous carbon as high performance symmetrical supercapacitor electrodes

•Pyrrole modified fungus was used to prepare supercapacitor electrodes.•Efficient and simple KOH activation method was used.•Hierarchical structure, high SSA (2959 m2 g−1) and conductivity were exhibited.•Excellent specific capacitance of up to 270 F g−1 was obtained.•Discharging at large current density (10 A g−1) was achieved.

Nitrogen-doped hierarchical porous carbon has been prepared via a direct carbonization of pyrrole modified biomass for using as electrochemical double layers capacitance electrodes materials. The hierarchical porous carbon features high specific area (2959 m2 g−1) and porosity, which originated from the etching, gasification and intercalation effect during heat treatment. Based on this unique porous structure, specific capacitance of 270 F g−1 at low current density of 0.1 A g−1 and 232 F g−1 at high current density of 10 A g−1 was obtained in 6 mol L-1 KOH electrolyte. Excellent cycles durability was obtained after initial charge/discharge, the high specific capacitance remained nearly unchanged for total 4000 cycles tested over a broad current density ranging from 0.1 to 10 A g-1. This study indicates that hierarchical porous carbon derived from pyrrole modified biomass is a promising electrode material for symmetric supercapacitors.

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